SSR, August 1, 97

1
PP16Follicle Corpus Luteum Development Chapter
8 pg 164-180 Chapter 9 pg 188-206
ANS 3319Dr. Michael J. FieldsUniversity of
Florida
2
Development of Follicle

• In the fetus, germ cells (oogonium) originate
  from the embryonic gut and migrate to the cortex
  of the embryonic ovary (in urogenital ridge).
• Collect in egg nests of primordial follicles.
• Oogonia undergo mitosis and they increase in
  number.
• Mitosis stops at birth.
• Primordial follicles do not restart development
  again until puberty.
• With the initiation of hormone signaling.

3
Primary Follicle to Corpus Albican
P.L. Senger
4
1º Follicle
Overview of Follicle Development
2º Follicle
Graafian Follicle
Ovulation
Egg

• Egg

Corpus Hemorrhagicum

• E2

Immature CL

• Estrus

P4 Maintains Pregnancy
Corpus Luteum
Atretic Follicle
Dying Reabsorbed

• Lacks LH/FSH
• Presence of CL, P4

Corpus Albican
Cycle
5
3) Tunica Albuginea (Dense layer of Connective
tissue)
1) Peritoneum
Embryonic Gut
2) Surface Epithelium
Embryonic Ovary
Cortex
Germ cells
A) Cell Nest
D) Graafian Follicle
B) Primary Follicle
C) Secondary Follicle
1o- 1 layer granulosa cells 2o- 2 layers
granulosa cells 3o- Tertiary/Antral/Graafian
Mature Follicle
6
Follicle Dogma

• Female born with lifetime supply of eggs.
• Cow (at birth) 100,000 oocytes
• Calf 75,000
• Old cow 2,500
• Human at birth has 1 million oocytes
• At menopause, human runs out of eggs
• Post-menopausal 1,000 oocytes.

7
Follicle Dogma

• With ovariectomy post-menopausal woman will
  start to cycle.
• Possible source of eggs believed to be bone
  marrow
• There are proliferative germ cells that can
  continue oogenesis and folliculogenesis in the
  postnatal ovary
• but, these germ cells did not initiate/complete
  prophase I or the follicle did not envelop the
  oocyte.
• Researchers still argue that the postnatal ovary
  itself has the ability to undergo oogenesis and
  folliculogenesis throughout life.
• Johnson et al (2004), Nature Byskov et al
  (2005), Differentiation Skaznik-Wikiel et al
  (2007), Differentiation

8
Primary Follicle

• Egg surrounded by a single layer of granulosa
  cells.
• Phenotype changes from squamous to cuboidal
• Gonadotropins not required for development of
  primary follicle.
• 1 - 3 follicles start development each day.
• Fewer than 1 of all oocytes reach maturity and
  ovulate.

9
Primary Follicle
M.J. Fields
10
Secondary Follicle

• Preantral oocyte is surrounded by 2 or more
  layers of granulosa cells.
• An increase in size of follicle and oocyte.
• Formation of zona pellucida (translucent
  membrane).
• Up to this point independent of gonadotropins.
• Now it is responsive to FSH.

11
Tertiary Follicle

• Fluid filled blister with an antrum.
• Fluid liquor folliculi.
• Small 0.2 - 0.3 mm follicles (antral).
• 2 mm follicle takes on dependency for FSH/LH.
• Antral to preovulatory follicle takes 42 days (2
  cycles).

12
Graafian (Tertiary) Follicle
M.J. Fields
13
Graafian Follicle

• Graafian follicle is a dominate tertiary follicle
  gt 10 mm in diameter that goes on to ovulate.
• Two types Dominant Subordinate.
• Subordinate follicles become atretic because of
  insufficient FSH.
• Dominant follicle overcomes FSH insufficiency.
• Dominant follicle needs LH to grow.
• It will become atretic if there is insufficient
  LH

14
Follicular Waves

• Follicles grow in waves.
• Up to 3 cohorts are recruited per cycle
• FSH surge from previous ovulation causes
  initiation of cohort recruitment
• Influence of P4 during luteal phase prevents
  maturation to Graafian follicle
• Graafian follicle first follicle in cohort to
  develop LH receptors
• Only LH surge will cause ovulation of Graafian
  follicle

15
(No Transcript)
16
(No Transcript)
17
Two Cell Production of Testosterone
Theca
Granulosa
LH LH Receptor
FSH FSH Receptor
cAMP
SCC
cAMP
aromatase
T
T
E2
Basement Membrane
18
1) Theca Externa
2) Theca Interna
LH
Theca Cholesterol
3) Basement Membrane
T
4) Granulosa Cells
T Granulosa
Aromatase
FSH
5) Cumulus Oophorus
E2
8) Vitelline Membrane
6) Corona Radiata
9) Vitellus
10) Nucleus (DNA)
7) Zona Pellucida
19
Graafian (Tertiary) Follicle
Basement Membrane
Theca Interna
Theca Externa
Granulosa
M.J. Fields
20
Graafian Follicle
3) Theca Interna a) LH Receptor b) Chol
Testosterone
4) Basement Membrane a) barrier to blood
vessel growth and large
molecules from blood
2) Theca Externa
Antrum Liquor Folliculi

• Stroma
• a) smooth muscle
• b) connective tissue

5) Granulosa Cells a) FSH Receptors b)
will develop LHR c) T E2
21
Graafian Follicle

• 6) Stroma
• Smooth Muscle

5) Theca Externa
Antrum Liquor Folliculi Fluid
4) Theca Interna
1) Oocyte/egg
3) Basement Membrane -barrier to blood
vessels -gt 50,000 mm
2) Granulosa Cells - FSH Receptors T
E2
22
Graafian (Tertiary) Follicle
Basement Membrane
Theca Interna
Theca Externa
Granulosa
M.J. Fields
23
Graafian Follicle
Egg Ovum
7) Vitellus
3) Corona Radiata granulosa cells
6) Vitelline Membrane
5) Perivitelline Space
2) Cumulus Oophorus granulosa cells
4) Zona Pellucida
1) Basement Membrane
24
Graafian (Tertiary) Follicle
Vitelline Membrane
Zona Pellucida
Vitellus
Corona Radiata granulosa
Cumulus Oophorus granulosa
M.J. Fields
25
Harvested Oocyte
Cumulus Oophorus Granulosa
Ovum
Zona Pellucida
26
Harvested Oocytes
Cumulus
Zona Pellucida
Corona Radiata
27
Harvested Oocyte
Zona Pellucida
Corona Radiata
Cumulus